The present invention relates to a defect inspection apparatus and method and, particularly, to an apparatus of measuring a precipitated particle in a semiconductor wafer and a crystal defect, such as a stacking fault, and to a wafer surface extraneous substance inspection apparatus.
As the integration of an LSI (large scale integrated) circuit is being increased, decrease in a conforming item acquisition ratio and decrease in reliability caused by a failed MOS (metal oxide semiconductor) transistor composing the LSI circuit becomes a big problem. As causes of the failed MOS transistor, dielectric breakdown of a gate oxide film and excessive current leak in a junction are typical problems. It is not preferable that a crystal defect is formed in a surface area having elements in a silicon wafer because a failed MOS transistor occurs, as described above.
Therefore, defect measurement is important in the quality control of silicon crystal. In regard to the method measuring such a defect, there is a method in which an infrared ray transmissible through the silicon is irradiated and the scattered light is detected.
Crystal defects exist and are distributed at any positions inside a single crystal. In general, in manufacturing devices such as IC or the like, it is required to develop a wafer which does not have any crystal defect within a range from the crystal surface (mirror surface) to a level of 0.5 .mu.m depth and contains high density defects in the deep zone.
In developing such a wafer, it is necessary to observe these crystal defects to reflect the observed result to the development. In regard to the observing method, there is described a technology in "Extended Abstracts of the 1996 International Conference on Slid State Devices and Materials, Aug. 26-29, 1996" and "Applied Physics, Vol. 65, No. 11 (1996)", pages 1162-1163.